// Parses a network that begins with 'R'.
Network* NetworkBuilder::ParseR(const StaticShape& input_shape, char** str) {
char dir = (*str)[1];
if (dir == 'x' || dir == 'y') {
STRING name = "Reverse";
name += dir;
*str += 2;
Network* network = BuildFromString(input_shape, str);
if (network == nullptr) return nullptr;
Reversed* rev =
new Reversed(name, dir == 'y' ? NT_YREVERSED : NT_XREVERSED);
rev->SetNetwork(network);
return rev;
}
int replicas = strtol(*str + 1, str, 10);
if (replicas <= 0) {
tprintf("Invalid R spec!:%s\n", *str);
return nullptr;
}
Parallel* parallel = new Parallel("Replicated", NT_REPLICATED);
char* str_copy = *str;
for (int i = 0; i < replicas; ++i) {
str_copy = *str;
Network* network = BuildFromString(input_shape, &str_copy);
if (network == NULL) {
tprintf("Invalid replicated network!\n");
delete parallel;
return nullptr;
}
parallel->AddToStack(network);
}
*str = str_copy;
return parallel;
}
// Builds a set of 4 lstms with x and y reversal, running in true parallel.
Network* NetworkBuilder::BuildLSTMXYQuad(int num_inputs, int num_states) {
Parallel* parallel = new Parallel("2DLSTMQuad", NT_PAR_2D_LSTM);
parallel->AddToStack(new LSTM("L2DLTRDown", num_inputs, num_states,
num_states, true, NT_LSTM));
Reversed* rev = new Reversed("L2DLTRXRev", NT_XREVERSED);
rev->SetNetwork(new LSTM("L2DRTLDown", num_inputs, num_states, num_states,
true, NT_LSTM));
parallel->AddToStack(rev);
rev = new Reversed("L2DRTLYRev", NT_YREVERSED);
rev->SetNetwork(
new LSTM("L2DRTLUp", num_inputs, num_states, num_states, true, NT_LSTM));
Reversed* rev2 = new Reversed("L2DXRevU", NT_XREVERSED);
rev2->SetNetwork(rev);
parallel->AddToStack(rev2);
rev = new Reversed("L2DXRevY", NT_YREVERSED);
rev->SetNetwork(new LSTM("L2DLTRDown", num_inputs, num_states, num_states,
true, NT_LSTM));
parallel->AddToStack(rev);
return parallel;
}
// Parses a parallel set of networks, defined by (<net><net>...).
Network* NetworkBuilder::ParseParallel(const StaticShape& input_shape,
char** str) {
Parallel* parallel = new Parallel("Parallel", NT_PARALLEL);
++*str;
Network* network = NULL;
while (**str != '\0' && **str != ')' &&
(network = BuildFromString(input_shape, str)) != NULL) {
parallel->AddToStack(network);
}
if (**str != ')') {
tprintf("Missing ) at end of (Parallel)!\n");
delete parallel;
return nullptr;
}
++*str;
return parallel;
}
// Parses an LSTM network, either individual, bi- or quad-directional.
Network* NetworkBuilder::ParseLSTM(const StaticShape& input_shape, char** str) {
bool two_d = false;
NetworkType type = NT_LSTM;
char* spec_start = *str;
int chars_consumed = 1;
int num_outputs = 0;
char key = (*str)[chars_consumed], dir = 'f', dim = 'x';
if (key == 'S') {
type = NT_LSTM_SOFTMAX;
num_outputs = num_softmax_outputs_;
++chars_consumed;
} else if (key == 'E') {
type = NT_LSTM_SOFTMAX_ENCODED;
num_outputs = num_softmax_outputs_;
++chars_consumed;
} else if (key == '2' && (((*str)[2] == 'x' && (*str)[3] == 'y') ||
((*str)[2] == 'y' && (*str)[3] == 'x'))) {
chars_consumed = 4;
dim = (*str)[3];
two_d = true;
} else if (key == 'f' || key == 'r' || key == 'b') {
dir = key;
dim = (*str)[2];
if (dim != 'x' && dim != 'y') {
tprintf("Invalid dimension (x|y) in L Spec!:%s\n", *str);
return nullptr;
}
chars_consumed = 3;
if ((*str)[chars_consumed] == 's') {
++chars_consumed;
type = NT_LSTM_SUMMARY;
}
} else {
tprintf("Invalid direction (f|r|b) in L Spec!:%s\n", *str);
return nullptr;
}
int num_states = strtol(*str + chars_consumed, str, 10);
if (num_states <= 0) {
tprintf("Invalid number of states in L Spec!:%s\n", *str);
return nullptr;
}
Network* lstm = nullptr;
if (two_d) {
lstm = BuildLSTMXYQuad(input_shape.depth(), num_states);
} else {
if (num_outputs == 0) num_outputs = num_states;
STRING name(spec_start, *str - spec_start);
lstm = new LSTM(name, input_shape.depth(), num_states, num_outputs, false,
type);
if (dir != 'f') {
Reversed* rev = new Reversed("RevLSTM", NT_XREVERSED);
rev->SetNetwork(lstm);
lstm = rev;
}
if (dir == 'b') {
name += "LTR";
Parallel* parallel = new Parallel("BidiLSTM", NT_PAR_RL_LSTM);
parallel->AddToStack(new LSTM(name, input_shape.depth(), num_states,
num_outputs, false, type));
parallel->AddToStack(lstm);
lstm = parallel;
}
}
if (dim == 'y') {
Reversed* rev = new Reversed("XYTransLSTM", NT_XYTRANSPOSE);
rev->SetNetwork(lstm);
lstm = rev;
}
return lstm;
}
